A combined cycle engine merges two or more distinct propulsion technologies into a single powerplant, allowing an aircraft to transition between them as speed and altitude change. A common setup integrates a conventional turbojet for low-speed takeoff with a ramjet or scramjet for high-Mach atmospheric flight. This approach eliminates the need to carry separate engines for different phases of a hypersonic mission.
The vehicle uses a combined cycle powerplant, running as a turbojet off the runway before transitioning to scramjet mode at Mach 3.
Related terms
Ramjet
An airbreathing jet engine that uses the vehicle's forward motion to compress incoming air.
Scramjet
An airbreathing jet engine that operates with supersonic airflow through its combustion chamber.
Turbojet
An airbreathing jet engine that generates all its forward thrust directly from high-velocity exhaust gas.
Hypersonic
Relating to speeds equal to or greater than five times the speed of sound.